1. Field of the Invention
The invention relates generally to systems for configuring cable in a movable cable chain and more specifically relates to retrievably storing cable chain in a compact format.
2. Discussion of Related Art
Cable chains (also known as drag chains, energy chains, and cable carriers) comprise flexible, segmented housings used to surround and guide cables that interconnect machinery and devices. Cable chains restrict the available range of motion of the cable(s) that they house, and further typically restrict a cable to substantially coplanar motion. In addition to the obvious benefit of maintaining order among a group of cables, such restricted movement of cables is generally desirable because if a cable is “kinked” or bent at too small of a radius of curvature, the cable may experience a degradation of signal quality, or may even fail entirely. By preventing cable motion that is undesirable (e.g., tangles, kinks, etc.), the cable chain thereby increases the reliability and durability of a given cable connection.
One application of cable chains is in the field of data storage systems. A storage network may comprise tens, hundreds, or even thousands of individual storage devices interconnected with storage controllers, host bus adapters, expanders, and host devices. In one exemplary configuration of storage systems, storage devices may be housed in blade drives/enclosures configured as swappable Customer Replaceable Units (CRUs), each CRU attached to a shelf in a rack. Such configurations may utilize numerous cables—cables that may couple individual storage devices and support electronics to a blade, cables that couple drive blades to other components in a rack, cables that interconnect racks of storage devices, etc. Because each storage system will often comprise various combinations of hardware and devices, it is not uncommon for storage systems to utilize cable chains to guide and protect the various interconnections. For example, cable chains may be used to guide/constrain inter-connection cables between drive blades and other components coupled within a rack, so that the blades may be more easily removed from and inserted into the rack.
Storage systems are typically configured to allow for reconfiguration via the insertion and removal of various storage system components. Additionally, storage systems are preferably designed to allow a field engineer or operator to access the hardware of the storage system in order to perform routine maintenance or to alter the configuration of the storage system. Unfortunately, it is often a complicated process to assemble or manufacture cable chains that have a shape memory allowing for easy access to hardware. Systems or devices that impart a shape memory onto a cable chain typically must be installed onto the cable chain itself utilizing specialized tools or other devices, thereby increasing the complexity (and therefore expense) of the final product.
Thus it is an ongoing challenge to create retractable cable chains that are simpler to manufacture and configure than existing designs.